Steam-jacketed kettle



May 29. 1924. f 1,494,979

F. SALISBURY STEAM JACKETED KETTLE Filed March 20, 1922 wrmzssassINVENTOR w Jim ATTORNEYS Patented May 20, 1924.

UNITED STATES ROBERT FLOYD SALISBURY, OF NEW KENSINGTON," PENNSYLVANIA}ASSIGNOR TO ALUMINUM COMPANY OF 'AMERICA, OF

PORATION OF PENNSYLVANIA.

STEAM-JACKETED, KE'ZPILEQ T 0 all whom it may concern.

Be it known that I, ROBERT F. SALISBURY, a citizen of the United States,and a resident of New Kensington, in the county of Vest moreland andState of Pennsylvania, have invented a new and useful Improvement inSteam-Jacketed Kettles, of which the follow- I v together throughout aline ofcontact and employmg a single row of rivets, or rivets widely ingis a specification.

This invention relates tokettles and particularly to steam jacketedkettles in which the-inner and outer shells comprisingthe walls of thesame are spaced apart to provide a steam chamber therebetween. v

Kettles of the class referred to are most frequently made of cup shapedshells, the bottom portions of which are of somewhat differentcurvatures, and the sides of which at some distance above the bottomsassume substantially the same curvature so as to contact throughout anannular zone. Heretoforethe' practice has been to rivet the two shellstogether in this zone, frequently with an interposed film of red lead orasbestos fibre, inan attempt to form a satisfactory joint to prevent,under service conditions, the escape of the heating medium admitted tothe chamber formed between the shells.

Experience has taught that with a construction as above described, anddue to the variations in expansion and contraction of the two shellscaused by changes and differences in the temperature to which they aresubjected, a decided shearing action is eX- erted upon the rivets, whichin course of time, terminates in the rupture of the shells adjacent tothe rivets, the breakage of the rivets themselves, or a distortion ofthe parts, permitting leakage. On account of the fact that the jointbetween the shells is accomplished by merelybinding the shells intointimate contact, as above described, it is very difiicult to preventleakage therebetween unless the-shells are made to contact throughout alarge area, which necessitates the employment of a plurality of rows ofrivets or such close spacing thereof as to weaken the metal of theshells, eithercon struction requiring the use of a large number ofrivets. Frequent attempts to find a suitable substitutefor such methodsof j oinf ing the shells, such as the welding or similar means, havebeen made but have proved un- JVQld'ed contact and. the rivets.

Application filed March 20,1922, Serial no, 545,389."

tendency of the shells to separate under the pressure of the heatingfluid employed in kettles of medium or large capacities, and

PITTSBURGH, EENNSYLVANIA, A 003- this is particularly true when dealingwith.

shellsfmade of metals havingthe physical characteristics of aluminum.

Ihave found that by Welding the shells spaced, and positioning themcomparatively closeto the weld, an effective sealed joint maybeobtained. The ,weld not onlyacts as an effective seal but eliminates theexistence of the film ofjair normally-present between duction of heatfrom' one shellto the other takes'place in substantially the same mannerasrif the shells were'formed of a single piece of metal. This assuresanalmost equal de gree of expansion or contraction in the twotemperature,andveliminates the shearing ac- "shells in the region oftheir welded joint re- ,gardless of the changes and variations intionldue to such differences in expansionand contraction, as-prev ouslynoted. The tendency to shearis also reduced bylplacing therivetscomparatively close to the weld so that anydifterence' in the rateof'expansion or contraction between the shells in said region thatmightjoccur will normally result in a negligible shearingefiec't onaccount of the small extent of metal between the line of Furthermore,the elimination of theshearing action upon the rivets necessitates theemployment betweenthe rows which tends to separate and distort theparts.

Theobjectof this invention is to provide a kettle of the kind referredtolwhich is free of the disadvantages above noted arising from the,employmentof the types of of a smaller numberthereof, or a single row rriveted joints mentioned for unitin A the shells. It is also an objectto provide a kettle in, which the shells-and rivets for binding the samein contact are of the same metal for the purpose of eliminating theelectrolytic or other similar action resulting in corrosion between theparts when metals of different kinds are employed.

It is still a further object to provide a steam jacketed kettlein whichthe body portions of the shells are connected by staytubes of novel formhaving closed bottoms which lie substantially flush with the exterior ofthe outer shell and welded thereto, thereby not only preventing leakagebut adding to the general appearance of the kettle. It is also an objectto construct the stay-tubes as well as the rivets and shells of the samemetal, preferably aluminum, so as to eliminate corrosion between thejoints, as previously pointed out in connection with the welded jointbetween the two shells.

These and otherobjects of the invention will more readily appear whentaken in connection with the following description and appended claims.

In the accompanying drawings Fig. 1 is a'fragmentary vertical sectionalview with parts-in elevation'illustrating the preferred embodiment ofthe invention; and Fig. 2 is aperspective view of one of the stay-tubesconnecting the inner and outer walls of the.

kettle. e

In the embodiment illustrated, 1 and 2 represent the inner and outercurved shells or walls of the kettle, the bottom portions of which arespaced apart to form a steam heating chamber 3 therebetween. The

shapes of the shells are such that the inner peripheral edge 4 of theouter shell conforms to the curvature and is adapted to contact theexterior of the inner shell throughout an annular zone in proximity tothe said edge. The edge of the shell 2 is welded to the shell 1 asindicated at 5 so as to form a hermetically welded joint, and the twoshells are bound into intimate-contact by a single row of spaced rivets6 disposed close tothe line of the welded connection.

. The welded joint '5 performs a double function. In the first place, itforms a Welded oint preventing the escape of the heating fluid betweenthe shells, and in the second place, it eliminates special packings orthe heatinsulating air film, previously men tioned, so that heat isreadily conducted from one shell to the other. This results in U keepingthe two shells adjacent their welded connection at substantially the 1same temperature, eliminating differences in-expansion and contractionin-the two shells at f that;v region together jwith the consequentshearing effect uponthe rivets used for binding, the walls together.Furthermore, the

lineof, rivets 6. is placed so close to, the welded olnt 5 that a. verysmall expanse of metal lies. between the two, thereby: also lesseningwhateverlsrnall shearing action that might still be exerted.

.l :The bottomportions of the shells are 4 connected at intervals by aplurality of'stayinner shell.

'when in the position shown in Fig. '1, said lip being welded to theinner shell throughout their line of contact 9. The bottom portion ofthe tube opposite its open end is completely closed and is adapted toproject into and fill an aperture in the outer shell, said tube andouter shell being welded throughout their line of contact as indicatedat 10. In this manner the stay-tube is firmly united with the-shells byhermeti cally sealed joints, and due to the fact that the bottoms of thetubes are completely closed, even if leakage should occur at the joint 9escape of the heating fluid would be prevented by the joint 10, and inaddition the whole exterior of the kettle is greatly improvedinappearance.

It has been found that when the walls of the kettle are madeof aluminumand the ,rivets or stay-tubes are made of a different metal, such asbrass, an electrolytic or other similar action is set up which resultsin'a pronounced corrosion at the jointslformed between the contactingparts of dilferent metals. Not only the walls of the kettle but also therivets 6 and tubes 7 are therefore made of the sameinetal.

The main outlet for the kettle is formedv end. The outlet is'preferablyequipped'with a strainer plate'20 perforated at 21 which. is supportedby resting at its periphery: upon the wall 1 and having acentral'aperture the edge of which engages the lateralribs ofasupporting cross indicateduat 22. o The supporting cross 22 islongitudinally tapered and is adapted to bepositioned by merely placingthe same within the aperture of the In this manner both the cross andthe strainer plate may be easily retained."

in position but readily removed whenever desired. a

The kettle is supported any suitable manner such as by a ring 25embracing the kettle and attached to the upper ends of a plurality ofspaced legs 26, as shown inFig. 1. Steam is supplied to the heatingchamher 3 through a suitably constructed inlet 27 and exhausted througha similar outlet 28.

It is thus seen that the invention provides a steam jacketed kettleaccomplishing the objects above enumerated in a simple and efficientmanner, and provides a durable structure not liable to be disrupted andwhich does not become corroded at the joints between the several parts.

I claim:

1. A steam jacketed kettle comprising an inner shell, an outer shellembracing the same but spaced therefrom to form a steam space betweenthe two, and a stay-tube of cup form connecting the two shells, the edgeof its lip at the open edge of the tube conforming to and contacting theouter face of the inner shell and welded thereto, the closed end of thetube projecting through an ape]:- ture in the outer shell and connectedtherewith also by welding.

2. A steam jacketed kettle comprising an inner shell, an outer shellspaced therefrom to form a steam chamber therebetween and provided withan aperture, a cup-shaped stay-tube having its peripheral liphermetically attached to the inner shell and its body portion fillingthe said aperture, said body portion and the outer shellbeing'hermetically joined.

3. A steam jacketed kettle comprising an inner shell, an outer shellprovided with an aperture and spaced from the first named shell to forma steam chamber, a cup-shaped stay-tube having its open end welded tothe inner shell and its body portion projecting into and filling thesaid aperture, the closed bottom of the tube lying substantially flushwith the exterior of the outer shell, the outer shell and tube beingunited by welding.

4. A steam jacketed kettle comprising an inner shell, an outer shellprovided with an aperture, the shells being spaced to provide a steamchamber therebetween, a cupshaped stay-tube having the raw edge at itsopen end conforming to and adapted to seat upon the convex surface ofthe inner shell, the cross sectional shape of the body of the tubecorresponding to that of the aperture 5. A steam jacketed kettlecomprising an inner shell, an outer shell provided with an aperture, theshells being spaced to provide a steam chamber therebetween, acup-shaped stay-tube having the raw edge of its open;

end conformingto and adapted to seat'upon the convex surface of theinner shell, the closed end of the tube projecting into and filling thesaid aperture, both said: shells being welded to the tube adjacent theirentire line of contact, the shells and tube being made of aluminum.

6. A steam jacketed kettle comprising an outer curved shell having aperipheral margin and provided with an aperture through the bodythereof, an inner curved shell disposed within the outer shell andspaced therefrom except in the region of said margin to provide a steamchamber, the inner shell contacting the portion of the outer shelladjacent its margin and united to its raw edge by welding, a series ofspaced rivets uniting the two shells in proximity. to their weldedconnection, a cup-shaped staytube having its open end conforming to andadapted to rest upon the convex surface .of the inner shell, the. closedend of which lies flush with the exterior of the outer shell, and fitsthe said aperture, both said shells being hermetically connected to thetube by welding adjacent and throughout their entire line of contact. 1V In testimony whereof, I sign my name. ROBERT FLOYD SALISBURY.\Vitnesses:

Jos. T. WEINZIERL, P. B. Hermon.

